Numerical Investigation of Drag Characteristics of a Tiltrotor Wing under Steady Blowing

During the tilt-transition phase, tiltrotor aircraft experience strong coupling between propeller slipstream and freestream flow. The wing surface flow becomes highly unsteady. Large-scale separation is likely to occur and causes a significant increase in aerodynamic drag. To address this issue, a numerical method for analyzing rotor-wing aerodynamic interference during the tilt-transition phase is developed based on computational fluid dynamics, combined with a momentum-source model. On this basis, a simplified wing-propeller configuration representative of the tilt-transition segment is adopted as the research object, and the aerodynamic characteristics under steady blowing on the lower surface of the wing are systematically investigated. Particular emphasis is placed on the effects of blowing-slot locations at different chordwise positions and of different blowing momentum coefficients on the drag characteristics of the wing. The results show that steady leading-edge blowing effectively weakens the attachment effect of the high-speed propeller slipstream on the lower wing surface. It significantly improves the local pressure distribution and reduces wing drag. As the blowing location moves toward the trailing edge, the coupling between blowing and slipstream tends to induce separation vortices and enlarge the separated region. This leads to a noticeable increase in drag. Proper selection of the blowing location and momentum coefficient can therefore achieve effective drag reduction during the tilt-transition phase.